1. Field of the Invention
The present invention relates to an illumination optical apparatus of the reflection type which guides an illumination light to a surface of an illumination objective (illumination objective surface), an exposure apparatus provided with the illumination optical apparatus, and a method for producing a device using the exposure apparatus.
2. Description of the Related Art
Recently, in order to enhance the resolution by shortening the exposure wavelength, an exposure apparatus (hereinafter referred to as “EUV exposure apparatus”) has been developed, which exposes a substrate such as a wafer via a reticle (mask) by using, as an exposure light beam (exposure light), an extreme ultraviolet light (hereinafter referred to as “EUV light”) which has a wavelength of, for example, not more than about 100 nm. In the EUV exposure apparatus, there is no optical member through which the EUV light is transmitted. Therefore, an illumination optical system, a projection optical system, etc. are constructed by using reflecting optical members, except for specified optical filters or the like. The reticle is also formed of a material of the reflection type.
The EUV light is absorbed by a gas. Therefore, the EUV exposure apparatus is installed in a vacuum chamber in which a vacuum atmosphere having an air pressure considerably lower than the atmospheric pressure is maintained (see, for example, Japanese Patent Application Laid-open No. 2004-152843). Further, as for a light source section, which includes a laser plasma light source, etc., is sometimes provided in a small-sized independent vacuum chamber in order to further enhance the degree of vacuum.